The present invention relates to an optical sight for a combat vehicle, in particular a sight of the periscope type, intended to be mounted in a weapon turret of the vehicle in order to achieve sight lines at elevations between roughly xe2x88x9210xc2x0 and 90xc2x0 of a weapon barrel mounted pivotably about a horizontal axis in the weapon turret, the sight comprising on the one hand a lower standard sight unit, which deflects vertical incident light by 90xc2x0 to an eyepiece, and on the other hand a top mirror, located above the standard sight unit and pivotable in synchronism with elevating movements of the barrel, likewise about a horizontal axis.
Periscopic sights for combat vehicles normally comprise a lower sight unit angled at 90xc2x0 and also, arranged pivotably above the latter, a top mirror which is interlinked with the barrel of the weapon so that the sight line follows the elevation of the barrel. This sight configuration functions well at low elevations of the barrel. At higher elevations, up to roughly 60xc2x0, very high mirrors are required in order for it to be possible for sufficient light to reach the main lens of the sight. At even higher elevations (up to 90xc2x0) of the barrel, sight functioning is practically and theoretically impossible in such a sight arrangement. For this, a new design of the lower sight unit would be necessary, in which the incident ray path is not vertical but is inclined at an angle of, for example, 45xc2x0.
One object of the present invention is to produce a sight which, using an inexpensive, existing lower standard sight unit with 90xc2x0 deflection, makes possible high elevations of the sight line. To this end, the sight according to the invention described in the introduction is characterized in that it also comprises a deflection prism which is positioned above the standard sight unit and has an upper surface which faces the top mirror, is inclined at roughly 45xc2x0 to the vertical and is designed to reflect totally incident light at an angle of roughly 45xc2x0 to the surface and less, but to transmit light which is incident at roughly 90xc2x0 to the surface, in addition to which the deflection prism has a reflecting surface which lies behind the upper surface in the light incidence direction and is inclined at a smaller angle to the vertical than the upper surface, the mirror being arranged so as to direct incident light parallel to the barrel essentially at right angles to the upper surface of the prism, so that the incident light, after reflection against the surface lying behind, can be reflected from inside against the upper surface in order then to be made to fall vertically into the standard sight unit.
Another object of the invention is also to make possible, in a sight of the new type, a direct view for the vehicle/weapon operator with simple means. This is achieved by virtue of the fact that a secondary prism connected in parallel optically with the standard sight unit is arranged after the deflection prism in the light incidence direction, which secondary prism is designed and arranged so as to receive light incident from the mirror and reflected from outside on the upper surface of the deflection prism and to deflect it towards a person operating the sight in order to make a direct view possible for said person by means of the necessary adjustment of the mirror therefor.